New member swapping 4.3 for 5.7 tbi

[gar925]

Hello All! I've been a frequent reader of the forum (especially recently), but never registered. I have a 1994 K1500 5-spd that I'm trying to finish up a 4.3 to 5.7 tbi swap on. I'm new to working on SBCs and not finding a lot of useful help here in WV.

I found the Jasper 5.7 in a 1990 Cadillac Fleetwood with 89k documented miles. Engine started and ran great in the donor. I have the 5.7 in my truck and running. Trying to button up a few things to get it running great. I'm using the 4.3 wiring harness and ECM with 5.7 sensors.

I'm currently getting a code 43 (ecm/knock sensor) and low idle. I've talked to some other people who have completed a 4.3 to 5.7 swap and they claim that the 4.3 chip can be used for the 5.7. The truck is running "ok," but I think it could be better. I ordered a Jet 29404-S chip and realized it wouldn't fit my 16197427 ECM. Jet tech support told me that I needed a chip for the 5.7 that their performance chip could piggyback on.

I'm having trouble finding the correct chip for my ECM. I figured it was time to join the forum and ask for expertise from someone who knows. Any help would be greatly appreciated.

[dave w]

I've been thinking most, if not all, 94 K1500 with a 5.7 would have an automatic transmission. Maybe you can program your own chip with the modified attached .bin file? You have the option of using an adapter board to use a chip you program for yourself, see attached pictures. I think the Code 43 is because you will need a different knock sensor. Based on personal experience, I would use the knock sensor for a 1994 K1500 5.7 liter with AUTOMATIC Transmission with the 16197427 computer.

dave w

[gar925]

I've been thinking most, if not all, 94 K1500 with a 5.7 would have an automatic transmission. Maybe you can program your own chip with the modified attached .bin file? You have the option of using an adapter board to use a chip you program for yourself, see attached pictures. I think the Code 43 is because you will need a different knock sensor. Based on personal experience, I would use the knock sensor for a 1994 K1500 5.7 liter with AUTOMATIC Transmission with the 16197427 computer.

dave w

I didn't have any intentions of programming a chip. I'm not certain how to get started. I'll have to look on the forum and figure it out.

The donor was an automatic that only used 1 knock sensor. The 4.3 had 2. I added a 2nd to the 5.7 that was for a manual shift. I'll try swapping that one out for a sensor for an automatic.

[1project2many]

The donor was an automatic that only used 1 knock sensor. The 4.3 had 2. I added a 2nd to the 5.7 that was for a manual shift. I'll try swapping that one out for a sensor for an automatic.

Both sensors should be from the 4.3 / 7427 if you are using a 4.3 / 7427 chip. Because the 7427 was never used with a manual transmission and 5.7, and because you have dual knock sensors, no stock chip will be exactly correct for your truck. You should find someone who can, or you should learn how to, program custom chips. And since you can pull off this engine swap then I'm sure you can program chips.

[gar925]

Both sensors should be from the 4.3 / 7427 if you are using a 4.3 / 7427 chip. Because the 7427 was never used with a manual transmission and 5.7, and because you have dual knock sensors, no stock chip will be exactly correct for your truck. You should find someone who can, or you should learn how to, program custom chips. And since you can pull off this engine swap then I'm sure you can program chips.

The knock sensors on the 4.3 didn't fit the 5.7. The auto trans donor came with one and I purchased one for a 5-spd (wasn't aware there was a difference) to go in the other side. I'll probably try Dave's suggestion and see if the KS for an auto trans will work.

This swap has been outside my budget for a while now. I'd like to find someone that can program and get me running as soon as possible. However, it would be nice to find someone that can both get me running and help me learn to program for future mods.

[dave w]

A Used 5.7 Liter Memcal / Chip is a low cost option? According to the information I have available to me, the Memcal / Chip (code BPSA) for sale in the ebay link below is for a 1995 Van 5.7 liter with Manual Trans using the 16156930 computer (electrically identical / interchangeable for a 16197427 PCM).

http://www.ebay.com/itm/CHIP-BPSA-35...xWBJim&vxp=mtr

More information on the 16156930 Computer http://www.gearhead-efi.com/Fuel-Inj...Information-31

dave w

[gar925]

A Used 5.7 Liter Memcal / Chip is a low cost option? According to the information I have available to me, the Memcal / Chip (code BPSA) for sale in the ebay link below is for a 1995 Van 5.7 liter with Manual Trans using the 16156930 computer (electrically identical / interchangeable for a 16197427 PCM).

http://www.ebay.com/itm/CHIP-BPSA-35...xWBJim&vxp=mtr

More information on the 16156930 Computer http://www.gearhead-efi.com/Fuel-Inj...Information-31

dave w

The ebay listing says "4L60E." Am I missing something? I'm assuming you are saying this is a good chip to program for my truck? I've read quite a few of your posts on the forum on various topics. If you say this is the chip I need, I'll order it.

[dave w]

The ebay listing says "4L60E." Am I missing something? I'm assuming you are saying this is a good chip to program for my truck? I've read quite a few of your posts on the forum on various topics. If you say this is the chip I need, I'll order it.

Order the chip. I used two different sources to confirm that chip code BPSA is from a 95 Van 5.7 liter / Manual trans.

dave w

[gar925]

Order the chip. I used two different sources to confirm that chip code BPSA is from a 95 Van 5.7 liter / Manual trans.

dave w

Ordered. Should arrive Friday.

Do you think this will be a direct replacement or will I still need to do some initial programming?

[dave w]

The chip might need some re-programming, depending on how "Stock" your 5.7 is or is not? If you have removed emissions, changed injectors, modified the exhaust system, or have an aftermarket performance intake the chip will very likely need re-programming. I would expect a factory 5.7 liter / manual trans chip would be a HUGE improvement from a factory 4.3 liter / manual trans chip for your engine swap.

dave w

[gar925]

Order the chip. I used two different sources to confirm that chip code BPSA is from a 95 Van 5.7 liter / Manual trans.

dave w

It may be too late to question, but neither my 4.3 or 5.7 had an ESC mounted next to the throttle body. Do you foresee this being a problem? I did a quick search on AutoZone for an ESC for the van and nothing showed up. Hopefully, that's a good sign.

Thanks for all your help Dave!

[gar925]

The chip might need some re-programming, depending on how "Stock" your 5.7 is or is not? If you have removed emissions, changed injectors, modified the exhaust system, or have an aftermarket performance intake the chip will very likely need re-programming. I would expect a factory 5.7 liter / manual trans chip would be a HUGE improvement from a factory 4.3 liter / manual trans chip for your engine swap.

dave w

The only thing that has been changed is the exhaust. The PO deleted the cat and installed a 2.5" y-pipe to 3" single with a glasspack. I'm able to use the current exhaust temporarily, but it's rusted out. I intend to go with 2.5" to an x-pipe and then... I haven't decided on mufflers yet. The PO also installed 33s, which I think made the 4.3 even more sluggish.

It won't be long before I'll want to make some changes. I've already got my eyes on a Lunati .468/.468 cam.

I guess now I need to figure out everything I need to get started datalogging and possibly try my hand at tuning.

[dave w]

It may be too late to question, but neither my 4.3 or 5.7 had an ESC mounted next to the throttle body. Do you foresee this being a problem? I did a quick search on AutoZone for an ESC for the van and nothing showed up. Hopefully, that's a good sign.

Thanks for all your help Dave!

The ESC is in the Memcal / Chip on a 16197427.

dave w

[gar925]

Update:

I picked up two knock sensors for a '94 k1500 5.7 w/auto trans and swapped out the ones for 5-spd. The check engine light is gone, but there doesn't seem to be much, if any, change while driving.

The chip I ordered should arrive by Friday. Hopefully that will take care of the low idle, rev limiter, and remaining issues. I'll post an update when I get the chip installed.

[dave w]

The wiring schematics I have access to show the V8 uses One Knock Sensor, and the V6 uses Two Knock Sensors. When you install the V8 Memcal / Chip, you might need to unplug one of the knock sensors.

dave w